1. Field of the Invention
This invention relates generally to a positive engaging clutch, and more particularly, to a synchronizing clutch suitable for split engine crankshaft operation so as to permit an engine to operate on less than all of its cylinders under light load conditions and on all of its cylinders under full engine load conditions.
2. Prior Art
In the past decade, the cost of gasoline has increased significantly as a result of the dwindling supply of fossil fuel and the dependence upon the supply of oil from foreign countries. Accompanying this trend is the increased awareness of environmental pollution, which has resulted in stringent pollution controls on today's automobile engines. Such controls increase energy costs for operation of the vehicle and have motivated the automobile industry toward smaller engines. Microprocessor technology has also advanced to a point where the automobile industry is adopting microprocessor based engine control systems which offer a more accurate control of fuel mixtures and spark time so as to increase efficiency.
In an effort to reduce fuel consumption, one manufacturer has combined a microprocessor engine control system with a variable cylinder drive scheme such that all cylinders are operated during engine acceleration; however, only six cylinders are operated during engine cruise operation and only four are operated during extended cruise conditions. In this known arrangement, the cylinders are not completely disabled, but are rather continuously operated by the crankshaft. That is, the pistons are continuously reciprocated within the cylinder, although spark and fuel is not supplied thereto. While the efficiency of such an engine is somewhat increased, the engine still suffers significant mechanical friction and pumping losses.
Obviously, a better solution would be to provide an engine wherein particular cylinders may be engaged and completely disengaged automatically thus reducing friction and pumping losses. In this case, the cylinders could be operated at peak efficiency while providing the wide variations in horsepower required by the vehicle between acceleration and cruise. Obviously, such a system requires a clutch mechanism for engaging and disengaging crankshaft sections so as to effectively disconnect selected cylinders as the engine reaches its cruise state. This process must be reversed as engine load conditions increase.
One very important requirement of such a clutch is that it must engage adjacent crankshaft sections in a single predetermined angular relationship so that the engaged crankshaft sections operate as a single crankshaft. Thus, the required clutch apparatus must include means for assuring that adjacent crankshaft sections are engaged in phase.